I like the Zues system better then the VOLVO. If the boat is in the US, the cummins dealer network is much better and parts are easier to find. Maintanence items are also cheaper then Volvo. I have always had issues getting quick service on Volvo's here in South Florida. Also the props face foward on the Volvo, and rearward on the Zues and I think it helps to protect them from floating debris a little better......I've had to wait weeks on simple parts for them. Also, the Zues system with the exhaust routed out the transom is a much much better choice in a fishing situation.

Thanks Cap. I've heard of software issues on the IPS that puts the drivetrain in a limp mode, anyone else? While I agree on your points regarding the Volvo parts and service, Cummins hasn't been that exciting lately either. Anyone here installed or worked on either system?

From the Lazzara website I could just see the new 76 with triple Zeus, the 75 and 92 has quad IPS1 and IPS2.

We are building our new 54 with triple IPS/600 and got a good result from the first test run. But the first boat is not yet finished so I can answer better after summer. Here in Sweden we have of course good access to Volvo Penta Service Centers.

The issue of forward facing props is not worse than any props under the hull I think, if you hit something you have to lift the boat.

Have been working with IPS installations for 3 years and the following observations or experiences might be helpful:

As a builder in Florida, you will have Doug Gerber as your key customer support ace, and I cannot imagine a better person for that responsibility. Straight talk and often hands dirty. With any luck, you will also get the "been there, done that" experiance wealth of Tom Eckel, who before his VP days, must have set a record of 106 full blown repowers in a year with 6 guys. He has coordinated all of Lazzara's VP installs.

Had major troubles with their raw water set up; pump first, then pressurized strainer. The small pieces of organic matter that come out of the blender (read rw pump) get pushed through the strainer and, counter to their insistence that they get flushed through, they end up gathering in cooling components as a black mass of decay inviting others to join. Beyond this, the strainer covers have been problematic, whether by defect or poor replacement, and often have become engine room irrigation systems. VP has finally substituted pressure cooker style lids, but does not seem in any hurry to put their strainers before the pump. We simply put Groco prestrainers on to address this, as you would with any other engine package.

Have not experienced significant delays in parts to customers or VP servicing dealers, other than the recent boost sensors that Bosch must have had quite a rotten batch of. Have seen snapped off drive units replaced in a couple days.

VP will insist on individual battery banks for each engine, with no emergency interconnect switch. The computers for each engine "need" their own power source to not be affected by spikes or degradation from the others, and to isolate them for troubleshooting. They want 900 cca batteries x 2, and it seems if they go below 700-800 together, steering alarms sound, as the engines start shutting off critical power to components in order to keep fuel injection up.

The fuel burn meters are extremely accurate, to within 3 or 4 gallons when estimating fill up requirements of over 500 gallons, and it is probably just the genset guessed rate that causes any error.

Like most computers, if you leave them running all the time, they tend to pick up little annoyances. I have found that if you leave the boat for extended periods, it's either good to shut the engine banks down during that time, or restart them fresh upon arrival. Many times an alarm can be taken care of and not seen again just by rebooting the girl's circuitry.

Not sure about what the noise does to fish, but the drive exhaust 3' down puts virtually no black indication on the transom.

The optimum fuel economy is spread out over a plateau of 600 rpm without significant penalty, not just a single sweet spot.

The forward facing props? I have no answer whether one is better than the other. What I can say is a customer ran his boat up the river system to Michigan in the spring, then said he had a strange vibration in his headliner. Of course he had "not hit a thing" in spite of the seasonal discharge of Midwest refuse to the Gulf. When hauled, 5 out of 6 props were dog-eared clean over, yet the boat still ran a wot of within 2 knots of normal. I told him that headliner vibration was so bad, it damaged his props.

That's very interesting. A client just told me of a 40'er D6-IPS 500 that had the transmissions replaced because of 'some sort of raw water problem'. Does anybody know if there is any systemic problem? This is the first I've heard about this.

The volvo people seem much more aggressive, I guess they have to be as Cummins has built in sales with brunswick products. Based on the reaction from the "man on the dock" during the last few boat shows, you'd think that shafts and rudders are a thing of the past. I'm not sold yet as the one vessel that I did sea trial (quad zeus 60 Hat) was (at least imo) a miserable failure of a boat.

That's very interesting. A client just told me of a 40'er D6-IPS 500 that had the transmissions replaced because of 'some sort of raw water problem'. Does anybody know if there is any systemic problem? This is the first I've heard about this.

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What I was told by Volvo Penta, is if the hull has some kind of pockets, the exhausts can be trapped and go back into the raw water inlet at extended idling, why a separate water inlet would be advised.

Is it a boat yet to be built, or are you re-engining an existing boat ?

Both systems require hull bottom and hull structure modification...
Zeus drives are mounted in the vertical axis and require recessed tunnels in the hull deadrise whether its a twin or triple installation.
IPS drives are mounted normal to the hull deadrise and twin installations dont require recessed tunnels but do require a mounting ring let into the hull deadrise. A triple installation requires a flattened keel area or recessed tunnel for the centreline drive.

Both systems will affect the draft to different degrees. Both will affect LCG and static trim in different ways.
Twin Zeus drives, being set in recessed tunnels, protrude below the keel less than twin IPS drives on a like for like hull. Obviously triple installations will protrude deeper again.
The tunnels Zeus require will make the stern sit deeper due to loss of buoyancy on a like for like hull, assuming weights and LCG between the systems are similar.
Zeus drives give similar draft to sterndrives, IPS drives give similar draft to submerged props running without tunnels.

Both systems affect the running trim and dynamic handling in different ways.
Zeus drives have the props well aft, so propulsion and steering axis relative to the boats LCG wont be too different to sterndrives or submerged prop drives with rudders. However, the tunnels required by Zeus take out a fair bit of aft running bottom which will affect running trim, turning heel and overall handling to some extent compared to sterndrives etc.
IPS drives have the props well forward, no tunnels. The propulsion and steering axis is closer to the LCG of the boat which give a different set of handling characteristics again, especially when turning.

If its a new buy, get a ride in a boat with each and throw it around a bit.
If its an existing boat and being re-engineered / re-engined, supply Mercruiser and / or Volvo as much hull design and weight info as you can up front.

Like most of my posts, it was rather generalised. We should remember that the various engineers / hydrodynamicists / naval architects involved in the development of these drive systems did not design the hulls these systems are fitted to. Successful applications rely on close collaboration between hull designer / builder and drive system manufacturer, and that whatever combination of hull form, power to weight, LCG etc works best with one boat model wont necessarily work best with another. Especially considering the drives are not trimable and their direction of thrust is always parallel to the keel of the section of hull they are mounted on. One thing I can say with some certainty whilst still appearing rather vague, is that as more and more applications are out there running around, and as more and more feedback and trials data from different boat manufacturers is available to the drive manufacturers, the more successful individual applications of these systems are going to be. Until an IPS can be coupled with a Cummins, and a Zeus can be coupled with a Volvo, we have to choose between two similar yet rather dynamically different systems with considerably different installation and application protocol, based on whatever criteria decides our engine manufacture preference.
I personally love these systems, they work very well and from what I've seen after optimising running trim / LCG during trials they meet the claims made and in some cases they exceed them. However, in basic terms they are no more than an appendage that carries very efficient props...they are a means to convert a bigger share of the engines brake horsepower into net propulsive force. This additional propulsive force, along with its associated directional vectors (straight ahead and hard turns) has to be fine tuned to the hull design and LCG...in many cases an existing hull design and LCG already optimised for a different drive system. I guess I'm bumping my gums a lot when all I have to say is already obvious to Shazam...theres more to this than just buying a pair of engines and 'pod' drives and bolting them to a boat.

What I was told by Volvo Penta, is if the hull has some kind of pockets, the exhausts can be trapped and go back into the raw water inlet at extended idling, why a separate water inlet would be advised.

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What are the first indications of the problem; high temp? And how soon after new are they showing up?

What I was told by Volvo Penta, is if the hull has some kind of pockets, the exhausts can be trapped and go back into the raw water inlet at extended idling, why a separate water inlet would be advised.

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What are the first indications of the problem; high temp? And how soon after new are they showing up?

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Well, how many minutes does it take to burn an impeller..? I think the engine will shut down as soon as the temp goes up.

Lets hope for the end users sake that this is not another "rebadged" engine that has been so well known for un reliability and non dealer support for a while now. By this I mean the re branded Mitsubishi engine sold as a Volvo with an output equivalent to around 800 ekW when used as a Genset Prime Mover.